Not without reason did Aonio Paleario call this engine of the Index ’a dagger drawn from the scabbard to assassinate letters’—­sica districta in omnes scriptores.[116] Not without reason did Sarpi describe it as ’the finest secret which has ever been discovered for applying religion to the purpose of making men idiotic.’[117]

[Footnote 116:  In his Oratio pro se ipso ad Senenses.  Printed by Gryphius at Lyons in 1552.]

[Footnote 117:  1st. del Conc.  Trid. vol. ii. p. 91.  The passage deserves to be Paul IV. designated in his transcribed.  ’Sotto colore di fede e religione sono vietati con la medesima severita e dannati gli autori de’libri da’quali l’autorita del principe e magistrati temporali e difesa dalle usurpazioni ecclesiastiche; dove l’autorita de’ Concilj e de’Vescovi e difesa dalle usurpazioni della Corte Romana; dove le ipocrisie o tirannidi con le quali sotto pretesto di religione il popolo e ingannato o violentato sono manifestate.  In somma non fu mai trovato piu bell’arcano per adoperare la religione a far gli uomini insensati.’]

Index Expurgatorius sixty-one printing firms by name, all of whose publications were without exception prohibited, adding a similar prohibition for the books edited by any printer who had published the writings of any heretic; so that in fine, as Sarpi says, ’there was not a book left to read.’  Truly he might well exclaim in another passage that the Church was doing its best to extinguish sound learning altogether.[118]

In order to gain a clear conception of the warfare carried on by Rome against free literature, it will be well to consider first the rules for the Index of Prohibited Books, sketched out by the fathers delegated by the Tridentine Council, published by Pius IV., augmented by Sixtus V., and reduced to their final form by Clement VIII. in 1595.[119] Afterwards I shall proceed to explain the operation of the system, and to illustrate by details the injury inflicted upon learning and enlightenment.

[Footnote 118:  Discorso Sopra l’Inq. vol. iv. p. 54.]

[Footnote 119:  These rules form the Preface to modern editions of the Index.  The one I use is dated Naples, 1862.  They are also printed in vol. iv. of Sarpi’s works.]

The preambles to this document recite the circumstances under which the necessity for digesting an Index or Catalogue of Prohibited Books arose.  These were the diffusion of heretical opinions at the epoch of the Lutheran schism, and their propagation through the press.  The Council of Trent decreed that a list of writings ’heretical, or suspected of heretical pravity, or injurious to manners and piety,’ should be drawn up.  This charge they committed to prelates chosen from all nations, who, when the catalogue had been completed, referred it for sanction and approval to the Pope.  He nominated a congregation of eminent ecclesiastics, by whose care the catalogue was perfected, and rules were framed, defining the